Planning on running a nitrous plate on my twin turbo 366. Yes, a 366 tall deck. Twin ebay t3/t4. Going to use a Snow methanol injection kit. Ideally run it on 93 but one station sells 100 octane so that's an option without relying on 110 and having to go to the track.

How should I tune it for a 100 shot of nitrous? I know it will vary based on boost. Any info helps. Especially things like what to look for on plugs, air/fuel ratio, and even plug temp ratings before nitrous. I suppose it would be best to start rich, with a colder plug, take away some timing, and see. I'm not looking for specific tuning info, more just guidance on things to look for. The plate does have a fuel solenoid.

Another thing I'm not sure on, and could be a different thread altogether is how do I know when I have enough or too much timing? Obviously it is too much when the internals become externals. I know what the rattle sounds like so maybe that's a solid way to know to let off and reduce timing. Its pretty harmless N/A but with the cylinder pressure I'm looking at... well... it may not be good.

Image link won't display but yes this contraption exists.

https://i.ibb.co/NjkqVKR/20220928-203756.jpg

I am aware of the ridiculousness of this project. This is entertaining.

https://youtube.com/shorts/l7rXQRoq_iA?feature=share
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Guess I'm on my own. No big deal.

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I’m confused. Are you using the “snow kit” As enrichment for the N20? Or are you using that independently and adding nitrous on top?

General rule is to drop 2* for every 50HP N20 shot. So assuming you have the car setup well in boost drop 4* out of it while spraying.

Listening for Knock won’t work. By the time you heard the rattle, it would be to late. Boosted cars (esp. ones with N20 assist) Will be finicky and quick to detonate if the tune isn’t perfect. Esp. on pump or lowish octane. E85 would be a different story. IMO you would drop the timing to a known overly safe level. Dial in the boost and nitrous AFR. Once that’s set, bump timing up slowly with a new plug in the hottest hole each run. Stop advancing timing when HP or MPH stops raising substantially for each degree. OR until the plug tells you its too hot. AFR will be dialed in on the WB02. Timing will be read on the ground strap. About ¼ to halfway down the strap is “ideal” and “safe”. If the heat mark is down into the bend you have to much timing. I’d start with a 7 heat range NGK plug. Possibly move up to an 8 if needed.

 

Thank you. I am using the nitrous on top of the turbos. The methanol kit, don't think I even need it at 10 psi. I will not go higher without it. Should add I do intend on removing the rods. It's a free motor. Would like it to see a couple weeks down the track.

 

For people to really help more they will need more info,
please add every engine detail ,
such as compression ratio. Mileage. How is fuel supplied for nitrous vs main rail/carb supply. How is the nitrous plumbed, plated or direct ported. Planning for 100% meth or 50/50 or whatever. What is the current state of the tuning. How is timing being removed for nitrous, what type of switch and system.
What sort of power does the engine make without nitrous.
What type of plug is normally used and what is the new plug and new gap you intend to run.
etc....

Literally need every detail. Of all the things one may do to an engine, nitrous is the most fickle and requires the most precision and attn to details.

general safety,
1. pressure test the entire setup from compressor cover to intake manifold. make sure it holds boost pressure completely.
2. Ensure all fuel system components are updated, clean filters, clean fuel tank, properly mounted pumps, clean lines, etc... thorough inspection of fuel delivery. Check fittings and minimize fittings to minimize fuel leaking. Plan for fuel spray events by placing shielding or shrouds to cover fuel spray from hot exhaust system in the event of an accident or loose fitting. Wrap and blanket the exhaust to keep heat out of the engine bay. Place shields between exhaust and fuel components.
3. Verify the timing is correct at high rpm under load. Use a dyno if needed just for this test. Make 100% sure the timing you think the engine is running is actually running.
4. Perform a compression test. Clean the intake manifold. Clean the ports in the head. Degreaser and wash everything clean. Make sure the carb is thoroughly clean. Use a high quality air filter. Never run the engine without air filtering. Make sure the gaskets all line up correctly for ports, no mismatching.
5. make sure the engine and trans mounts secure. Additional bracing from head to chassis using a rubber vibration resistance attach point is recommended. Inspect trans mount and verify pinion angle if applicable. make sure driveshaft and it's joints are quality and cared for.

 

My advice is to not use the nitrous. You should spool the turbos easily with that emgine. I have a Buick 350 with twin 58mm T3/T4 and it spools super quick. I had a nitrous setup installed but I removed it once I realized it was just going to complicate the setup and reduce the reliability.

 

.96 T4 78/75's on mine and spools them just fine without nitrous on a mild 5.3 as well.

But def. need the right converter and a trans brake. I'll say if that's not an option, I sprayed my setup for less than a second to get the turbo spooled up and it worked amazingly well. Just need enough self control to let go of that button! lol (my ECU did it for me)

 

All good advice. Would like to thank F4k for the detailed advice too. I am going to nitrous this motor. I know it's going to melt. The motor was free. I'd love to stroke a 427 and jam it in there with the 80 mm turbos I have.

However. I am going to see what this dumpy motor can do. So I do appreciate the advice.

 

Finally had time to get into a real reply.

The engine is factory, but it has been bored. Unknown mileage. I took it apart and did a gasket kit. It was, surprisingly extremely clean. As in spotless. Lifter valley looked like it never even had seen oil. Matter of fact it looked like it was powdercoated red. I highly doubt that. But the fact remains. It was coated. And it was spotless. It is .020 over. Small dome pistons. 118cc chambers (give or take, i had to measure the heads myself). 1.94/1.6 valves, 236cc intake runners and 59cc exhaust runners. Yeah. I was surprised at the massive intake runners and tiny exhaust. I measured them 3 times and looked up the part number on the heads. Its actually a 427 head. Not sure thats better. Exhaust side still isnt great. More than likely pregapped rings. No, I did not check ring gap. I bet it's too small. So that's a thing to consider.

I'd guess factory replacement piston. There was no info that came up based on the part number on the pistons. More than likely an older rebuild. Probably 9:1. Motor came out of a box truck. I can't even say it came out of a box truck as it came out of a frame that was torched. It had an Allison transmission attached. Pretty sure whatever it was was either box truck or school bus. I did not cut the frame up or remove the motor. It ended up sitting attached to the 545 Allison at my old job for a year and then I got offered it for working a Sunday on top of overtime. Then all 1500 lbs got dropped in my driveway.

It was a TBI motor so it's like a 90 or 91. It is a Gen V block as it has no boss for a mechanical fuel pump.

I swapped the TBI intake for a stock carb dual plane intake. I didnt think an aftermarket single plane would benefit, even though I normally use those. It just wont have the range to make use of it. The TBI intake had tiny ports that were like half the size of the head ports. The carb intake had ports that perfectly matched. Seemed like an easy decision.

It's a plate nitrous system with separate fuel and nitrous solenoids. The fuel side I'm going to plumb off the regulator with the feed to the bowls. 6 an out of the regulator to the bowls and plate like aeromotive recommended. Nitrous side, well, you know where that goes.

Not 100% methanol. Methanol injection and 93. I'm not opposed to 100 or 110. There is a station not too far I can get both. This is now a track toy.

Locked out factory HEI for now at 20 degrees. I do want to upgrade to an msd with the boost timing controller. For now, it's locked. I am not made of money.

Running a factory tank with 8 an supply and return from a welded in sump. Aeromotive A1000 pump. Aeromotive boost referenced regulator.

Intake and heads have been thoroughly washed. I did run the motor on a stand before I put it in. Yes. With the turbos.

Car has solid motor mounts, poly trans mount, subframe connectors, solid aluminum body mounts (yeah i opted to wedge the front subframe and lower it the extra 1/2"), and Hotchkiss springs. I do have a 10 point cage that i need to install as well. Do need a driveshaft loop, 5 point harnesses, fire extinguisher, and some sort of traction device. It has a 4.10 with a locker. I may put a different gear in to actually reduce the torque.

Engine should make 230-250 hp and 350 lb ft NA. Not looking to reinvent the wheel, just want to have fun.

I know there are better motors out there. This motor was free. Everything around the motor can be swapped to something different. Like a Dart Big M. And trust me, I would love to build that, but this is what I have to work with at the moment.

 

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Like I said, the motor was very clean inside.

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Better pic of pistons. I am sure this motor is no more than 9:1.

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This is how I fit it in the car.

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Yep. I sealed my welds in JB weld in case I had any leaks.

 

That coating in the valley is probably glyptal, rather than powder coat.

Looks like a good foundation. Nothing wrong with building from free/cheap.

 

Doesn't really matter but good knowledge to keep in mind.

 

Well. I guess I'm just going to call holley. I am not afraid of this build. It needs to put power down.

 

Changed my mind. Number 1 I was wrong about the gas station. They don't have 100, they have 110 which I'm totally ok with. Picked up 5 gallons today since I plan on starting this the day after tomorrow. I think maybe I won't nitrous it, but it's good to have the option.

 

Now it's real. Fun day.